# complement

/ˈkɑmpɫəmənt/ (US) · /kˈɒmplɪmənt/ (UK)

Source: https://englishreference.com/word/complement
Updated: 2026-06-20

## Senses

### 1. to improve or complete

verb · CEFR B2

to add to something in a way that improves it or makes it perfect.

For teachers: to contribute extra features to someone or something in such a way as to improve or emphasise their qualities.

- The blue tie really complements your grey suit.
- The minimalist production design complements the stark, emotional themes of the play without distracting the audience from the performances.

### 2. a perfect partner

noun · CEFR B2

a person or thing that goes well with something else.

For teachers: a thing that contributes extra features to something else in a way that improves or emphasises its quality.

- The delicious sauce was the perfect complement to the grilled fish.
- The new CEO's focus on operational efficiency proved to be a vital complement to the founder's creative vision.

### 3. the full amount

noun · CEFR C1 · Formal

the total number or amount of people or things needed for something.

For teachers: the full number or quantity required or allowed to make something complete.

- The ship finally had its full complement of sailors and was ready to sail.
- The department is currently operating with a full complement of staff for the first time since the restructuring began last year.

### 4. grammar

noun · CEFR C1 · Technical

a word or phrase that follows a verb and gives more information about the subject or object.

For teachers: a word or phrase, especially an adjective or noun, that is used after a linking verb to complete the predicate.

- In the sentence 'She seems happy', the word 'happy' is a complement.
- The professor explained that while some verbs are intransitive, others require a complement to form a grammatically complete sentence.

Usage: In the sentence 'He is a doctor', the phrase 'a doctor' is a subject complement.

### 5. math and science

noun · CEFR C1 · Technical

an amount or set that, when added to another, makes a whole.

For teachers: the amount or set required to complete a whole, such as an angle that makes a right angle or a set of elements not in a given subset.

- The complement of a 30-degree angle is a 60-degree angle.
- In set theory, the absolute complement of set A consists of all elements in the universal set that are not members of A.

## Examples

- The red wine is a perfect complement to the steak.
- The new software serves as a necessary complement to the existing hardware, allowing the system to reach its full processing potential.
- In linguistic analysis, the subject complement provides essential information that follows a linking verb to describe or rename the subject of the sentence.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.